Friday Fact – 10th October 2014

Did you know, hurricanes, cyclones and typhoons are different names for the same weather phenomenon?

In general large cyclonic storms in the Atlantic and East Pacific are called hurricanes, those in the Indian Ocean are called cyclones while typhoons are the same weather events in the western Pacific.

More Information:
[1] Check out our blog post on these incredibly energetic weather events.

 

Japan hit by Super Typhoon Neoguri

The violent super typhoon Neoguri is possibly the most powerful typhoon to strike Japan in 15 years. With expected wind gusts of 170 miles per hour and 75 millimetres of rain per hour the typhoon is battering the southern islands of Okinawa this morning.

Neoguri is forecast to continue northwards over land passing over the southern island of Kyushu and onto central Japan slowly losing energy along the way.

Typhoon Neoguri is carrying a huge amount of moisture. When it hits the mainland much of that will be released as rain, which could unleash flash floods and trigger landslides, our correspondent adds. Storm surge wave heights of 12 metres are expected raising fears of further coastal flooding.

Check out one of our earlier posts for a discussion of how these large cyclonic storms form.

Typhoon Neoguri, the first super typhoon of 2014. Source: EPA/NOAA

 

More information:
[1] http://www.bbc.co.uk/news/world-asia-28189409
[2] https://climateandgeohazards.wordpress.com/2013/10/07/cyclones-hurricanes-and-typhoons-whats-the-difference

 

 

Category 5 Super Typhoon Haiyan

With wind speeds of 195mph and a diameter exceeding 1000km the category 5 super typhoon Haiyan could well be the largest storm in history!

Although the record books are probably the last thing the people of Philippines are worried about right now as the storm ravages the country.
The above image from the Guardian website shows the expected path of the typhoon over the next few days. The storm is expected to decrease in strength as it moves across the South China Sea.

Strong Winds From Typhoon Danas

Incredible footage of strong winds from Typhoon Danas which struck Okinawa, Japan on the 7th October. The typhoon has now weakened into a tropical storm but is still currently moving northwards towards northern Japan and Korea.
(© TyphoonHunter)

More information at: http://www.accuweather.com/en/weather-news/japan-typhoon-danas/18546539

Cyclones, Hurricanes and Typhoons: What’s the difference?

Having now entered the second half of the Atlantic hurricane season I thought it time to write up a short post about these powerful natural events.

First we must resolve an important issue: what is the difference between cyclones, hurricanes and typhoons? The answer is: there is no difference! These are just different names for the same weather phenomenon originating in different geographic locations.

Tropical storms are characterised by their geographic origins. (NASA)

Hurricane Genesis

Hurricanes are very large storm whose birth originates in the tropical oceans. They rotate about a central axis commonly called ‘the eye’. The oceans are a massive source of heat energy. Variations in the sea surface temperature result in pressure differences in the atmosphere which cause storms to build up.

To be classified as a hurricane a storm must reach wind speeds of at least 74 miles per hour. The rotation of the Earth gives these storm their characteristic spiral shape. Cyclonic storms in the northern hemisphere rotate anticlockwise while those in the southern hemisphere rotate clockwise.

Hazards

The main hazards from hurricanes are strong winds (up to 150 miles per hour for the very large events) and high volumes of rain. Hurricane winds can uproot trees and destroy houses. Large amounts of rainfall in a short period of time result in floods and rising groundwater tables.

The water-clogged landscape remains unstable, with increased risk of landslides and surface failures for many years after a particularly large event. For example, there were increased number of landslides in Taiwan for 6 years after Cyclone Bhola.

Extensive damage after the 2005 hurricane Katrina. Total damage > $100 billion USD.
(Mark Wolfe)

Historically significant hurricanes

The effect hurricanes have on people’s lives is depicted in the word hurricane itself; after the Caribbean god of evil, Hurrican. They are a devastating force of nature.

• The 1970 Cyclone Bhola is historically the worst event for deaths with reported numbers as high as 500,000 people dead, mostly in Bangladesh.

• Hurricane Katrina which struck the east coast of the U.S. in 2005 is the most costliest hurricane with overall damage exceeding $100 billion.

• The 1979 Cyclone Tip was the most intense hurricane ever recorded with wind speeds around 190 miles per hour. It was also the largest hurricane with a diameter around 2,170 kilometres.

• Hurricane Sandy (U.S. east coast, 2010) was an abnormally large event due to the fusion of a tropical hurricane and a winter storm. With rising temperatures due to global warming these hybrid-storms are expected to become more frequent.

What can we do?

Cyclone Mahasen hit Sri Lanka, Bangladesh and Burma earlier this season in May and resulted in far less deaths than expected thanks to swift action from the local governments. This shows that rapid response can save lives.

Proper preparation and sufficient warning can save thousands of lives every year.
(Geoffrey Alan)

Houses with appropriate shelters (as in the U.S.) need to be built in hurricane prone regions. Proper training should be given from early school level onwards on the appropriate actions to take before and after such events: e.g. having enough clean drinking water, tinned food, spare batteries for lights, mobile phone chargers, first aid kits etc.

Have a rapid response system in place from the national governmental level to manage pre-event evacuation (if needed) and post disaster recovery.

There is no clear agreement on what sort of affects climate change and global warming will have on hurricanes. However most scientists agree that the change will be for the worse whether it is in the form of increased number of hurricanes each year, increased size of the hurricanes or changes to the length of the hurricane season is uncertain.  We need to investment more into understanding the science behind these storms and the affects global warming will have on their magnitude and frequency of occurrence.

Ekbal

More information:
[1] National Hurricane Centre
[2] George M. Dunnavan & John W. Dierks (1980). An Analysis of Super Typhoon Tip (October 1979), Joint Typhoon Warning Center,1980
[3] www.weather.com/maps/news/atlstorm18/gulfofmexicosatellite_large.html